Batman rescued her

Before Tim could respond to Brainiac...

BOOM!

The ceiling to the metallic room burst open.

THUD!

A heavy bat-shaped suit of armor slammed down.

"Tim, is that you?"

Batman called in a metallic voice, his face completely sealed behind the thick armor. Disbelief in his tone. What had that sick alien done to him?

"Y.. yes! It's me!"

Tim called back with joyous desperation.

"Another earthling intruder, no matter."

Brainiac's face on the screen said as the tendrils started attacking Batman's suit as he began fending them off. They pulled and ripped at the armor but it proved too resilient, they couldn't find any loose material or gaps in the armor to take advantage of.

"Fascinating, an earthling using Kryptonian technology."

Brainiac observed through the screen looking at Batman's suit, his tone having a trace of surprise but also annoyance.

"If only I hadn't surpassed Kryptonian technology long ago."

He continued, piling on more mechanical tendrils to attack Batman, only these still did little to him.

"You're out of date Brainiac. The Kryptonian tech on this planet has continued to advance long after Krypton's destruction, and seeing as you have fought Superman multiple times, we've developed a few countermeasures for your machines."

Batman said before ripping his way out of all the tendrils, sending their parts flying to the floor.

"Needless to say, I called in a favor."

Batman rushed over to Tim.

"Hold on."

Batman said as he grabbed Tim, holding her feminine body in his arms before rocketing off through the hole in the device wall, dropping a series of small orange devices on his way out that beeped loudly. Batman crashed back out into the Gotham sewers and out into the night sky cradling Tim carefully ensuring she didn't fall.

"Wait, won't he try to come after us?"

Tim asked nervously.

"Not likely."

Batman responded as Tim's eyes were drawn down to an explosion from the sewer tunnel.

"Clark told me it was a scout pod, not designed for pursuit or combat, and what defenses it had I just ripped through. Had I been any later you may have been teleported to Brainiac's ship, J'onn's on the Watchtower scanning for any orbiting signatures." He explained.

"You're safe, Tim."

Batman said in a warmer tone.

"Bruce, how did you find me?"

"The energy signature you went to investigate. Clark called me, said the fortress detected Brainiac's signature in the same vicinity. By the time I got to the cave you'd gone, my suit tracked you until I lost your signal, thankfully you weren't too far from where your signal vanished."

Tim was more relieved than she'd ever been in her entire life. She looked down at her new form, the wind blowing her lengthened auburn hair into her face as she took in the outfit and general shape of her new body. She felt as though she was on the verge of tears realizing how much Brainiac had taken from her.

"Bruce, I'm..."

"We'll deal with it once we're back at the cave, I've called in for Clark and he should be there soon. He said there was a chance Brainiac would try something like this."

Minutes later they arrived at the Batcave, Bruce carefully lowering Tim down as he headed over to the bat computer.

Tim took a moment as she tried to steady herself, turning her torso as she inspected her new form again, it was still a lot to take in. She took a step forward, expecting to stumble suddenly, but instead found that she had no trouble adjusting to her new proportions and center of gravity, perhaps a side effect from the transformation. She took a few moments to collect herself.

"I'm sorry I let this happen to you Tim."

Bruce said with his head hung low at the bat computer.

"If I'd only been there sooner."

Batman spoke in both a saddened yet angry tone. Guilt laced his words. First Jason, then this.

"Don't do this guilt routine again. I knew exactly what I was doing, I chose to investigate it alone, I could've waited for backup and need I remind you, you're only one man! You can't be everywhere at once, even Clark and Barry can't do that. I chose this, we all did, and we knew the risks and that we'd have to live with the consequences."

Tim snapped, approaching Bruce.

Bruce turned, clearly moved by Tim's words, throwing the traces of a slight smile.

"What?"

Tim asked.

"You really are stronger than I am. Even after everything you've been through today, you're taking it better than me."

Bruce said in a quiet yet proud tone, before heading off to remove the Kryptonian suit and replacing it with his traditional batsuit.

"I don't know, you don't seem too freaked out by my new... well everything, heck you didn't even question whether it was really me or not."

Tim gestured to her chest.

"I saw Diana get turned into a pig once and I had to sing the blues for a witch to get her changed back. After that any sense of weirdness went out the window."

Bruce responded, causing Tim to nearly chuckle, had The Batman just tried to make a joke?

"Once Clark gets here we'll fix this, I promise."

Bruce said, walking back over to Tim.

"But... you don't know if that's even possible."

Tim replied, trying to still sound optimistic, but her feminine voice had a trace of sadness to it. Both she and Batman knew there was a chance that she'd be stuck this way.

"Tim. I promise. If we can't reverse engineer the technology he used to do this, we'll try other methods."

Bruce said more sternly, clearly covering the fear and sympathy he had for Tim, although for Tim it came through loud and clear. If science didn't fix this, he knew a very skilled magician.

Tim again felt herself on the verge of tears and couldn't help but reach up and wrap her arms around her mentor's shoulders in a hug, which Bruce reciprocated.

The heartfelt moment was cut short however when Tim went from having her eyes closed with a pained smile, to suddenly a cold emotionless expression with black out eyes.

Something then silently protruded from her wrist, a small sharp metallic tendril that jabbed right through Bruce's cowl and into his neck.

Bruce recoiled in pain as Tim let go, her eyes blinking back to the way they were before along with emotion flooding back to her face.

"What just happened? Bruce, what's wrong?"

She asked confused and concerned, before seeing the small needle-like tendril pulling back into her arm.

"Oh god, what have I done?"

Tim asked, horrified.

Bruce was still reeling in pain as his body began to churn and twist, crunching and snapping as Tim saw his pained face through the cowl turning an emerald green and narrowing, along with the tone of his groans shifting to a higher pitch. He fell to his knees as his thighs jiggled out into larger forms along with his hips pushing out as his lower legs thinned. All the while Bruce clutched at his cowl before with inhuman strength he ripped it in half and it tumbled to the ground, sending long blonde hair cascading down over his face.

He held onto his head in pain as his muscles at his arms and torso slimmed down to flatter toned forms, his arms and shoulders losing mass along with his thinning waist. A deep yet feminine moan escaped his lips as Tim heard his suit strain from his inflating ass pushing out, all before...

"GUH!"

A quicker, sharper moan escaped Bruce's lips as a wet crunch came from his crotch as his penis slipped up inside of him whilst a female reproductive system formed in its place.

Tim looked horrified, how could she have been stupid enough to think that the changes to her body were merely surface level, now all she could do was watch on helplessly as her mentor went through a similar experience to what she had mere minutes ago.

Bruce threw his head back revealing a feminine face, which was long and sharp, before a further straining came from his chest as with a fleshy shunt and slight jiggle a pair of breasts emerged, sticking out against his partially strained suit. Bruce panted heavily as he knelt on the floor, most of the changes seeming to cease momentarily, before his body froze, mouth still agape as his eyes went black, before out from his forehead emerged a device, unmistakably in the shape of Brainiac's symbol. Moments later he blinked and his eyes cleared again and he resumed panting, although it gradually slowed as 'she' came to a rest.

"Bruce?"

Tim asked, approaching nervously.

"Tim... I..."

Bruce began to speak but stopped at the sound of her voice, before taking in her new body as she slowly stood up. She was still much taller than Tim, and had a much more mature and sterner look with her sharper face, and she still seemed rather broad with the bat suit still somewhat fitting her, albeit having shifted slightly.

Just then the pair's attention was drawn to the sound of footsteps as someone entered the cave.